The Alaska Bird Observatory (ABO) operated a large, standardized spring mist-netting station at Creamer’s Field Migratory Waterfowl Refuge in Fairbanks, Alaska from 1992-2001. Approximately 150 migration-monitoring sites are located throughout North America, of which Creamer’s Field Migration Station (CFMS) is the northernmost. The location of CFMS is the near the northern limit of the breeding range of several species of boreal-forest landbirds that have undergone population declines in other portions of their geographic range. Migration monitoring provides important information for studying population trends in Nearctic-Neotropical migrants by sampling large movements of many species of birds that are not adequately sampled by point-count methods.

The objectives of the mist-netting study are to capture and band migrating passerines to examine: 1) population dynamics; 2) timing of life-history events (e.g., migration, reproduction, molt, juvenile dispersal, and seasonal differences in body condition); and 3) habitat use. Research at ABO has an important educational component, as the migration station has become a popular destination for local school groups, naturalists, bird enthusiasts, and international visitors. The objectives of the education program are: 1) to provide public education programs relating to avian identification, ecology, migration, and conservation; 2) to encourage volunteers from the community to participate in hands-on research; 3) to provide training in mist-netting and banding techniques to biologists from throughout Alaska.

The Alaska Bird Observatory has worked cooperatively with several state and federal agencies to accomplish several of the goals set by Boreal Partners in Flight to further the conservation of landbirds in Alaska. Additionally, data provided from CFMS support the goals and objectives of the Bureau of Land Management (BLM) nongame migratory-bird habitat conservation program. Finally, the ABO education programs are in line with the one of the legislative purposes for which Creamer’s Refuge was established; to provide the opportunity to view, photograph, and study various species of plants, wildlife and geological features typical to interior Alaska (AS 16.20.039). To accomplish this objective, the Alaska Department of Fish and Game (ADFG) may authorize the use of Refuge lands and facilities by other organizations for conducting educational and research programs.

Methods

Twenty-six standard 12m mist nets were opened at 05:30 and closed 6 hours later from 25 April-7 June (weather permitting). Mist nets were operated on alternate days from 25 to 30 April. Nets were checked and birds were removed from nets at 30- to 45-minute intervals. Birds were banded with United States Fish and Wildlife Service bands, and data were collected to determine size (using wing-chord and tail measurements), age, and breeding condition (using incubation patches in females and enlarged cloacal protuberances in males). For a detailed description of the methodology see Pogson et al. (1996).

Results

Capture Summary
We captured 454 individuals of 30 species (Table 1) during 34 days of mist netting (5,137 net hours of operation). The most abundant species were Violet-green Swallow, American Robin, Myrtle Warbler, Slate-colored Junco, and Common Redpoll (Table 2). Return rates continue to be high at our site, as nearly 9% of captures in 2001 were birds banded in previous years.

We captured high numbers of Solitary Sandpipers (Table 2) during 2001. Capture rates of Gray-cheeked Thrushes, Swainson’s Thrushes and Wilson Warblers were lower than in previous years (Table 3)

The mortality rate at our site continues to be lower-than-average for mist-netting studies. Our mortality rate of 0.2 % in spring of 2001 is well below the accepted average of 1-2%.

Education

Banding Demonstrations
Scheduled groups were presented with a standardized curriculum designed by ABO. ABO presented 42 groups (1,252 people; Table 4) with bird-banding presentations, bird walks, and seminars at Creamer’s Field. Unscheduled guests were greeted by staff, interns, and volunteers and presented with a banding demonstration relating to avian ecology and conservation.

Volunteers

Thirty-one volunteers assisted with the operation of CFMS by providing 550 hours of assistance. Volunteers received training in removing birds from mist nets, net maintenance, bird identification, recording data, and holding birds for public demonstrations.

Training

We operated our tenth annual training program for wildlife professionals from14 May to 25 May. The training program included hands-on training in methods of capturing and banding passerines. Additionally, the program included a lecture component that focused on objectives of netting programs and identification of bird species or plumages not observed in the field. We trained three biologists during this two-week program. These biologists were employees of the United States Fish and Wildlife Service and the Institute for Bird Populations.

Discussion

Captures of Solitary Sandpipers were unusually high during 2001, likely because of high water levels in the seasonal pond. Conversely, capture rates of Gray-cheeked Thrushes, Swainson’s Thrushes, and Wilson’s Warblers have declined during the 10-year spring netting period at Creamer’s Field. These declines will be monitored closely to determine whether they are detected during autumn netting or during point-count surveys.

Management Implications
Understanding movements and population dynamics of passerines has become an international concern due to recent documentation of population declines throughout North America (Rappole and McDonald 1994, Askins et al. 1990). Establishing baseline population data for different species is crucial in order to take management and conservation actions before a species becomes threatened or endangered. Furthermore, baseline monitoring allows land managers to set management priorities (e.g., habitat preservation) based on scientific data. Long-term data collected at CFMS is important for understanding population dynamics of migratory songbirds in interior Alaska.

Acknowledgements

We would like to thank the many ABO volunteers who contributed to the set up of our new banding lab and the operation of mist nets. The skill and dedication of ABO staff was instrumental in the success of another field season; many thanks to Nancy DeWitt, Dave Shaw, Andrea Swingley, and Jackie Weicker. The ABO Scientific Advisory Council provided valuable expertise and guidance in the operation of the station. We also thank John Wright and Mark Ross of the Alaska Department of Fish and Game for their and support.

This project was funded primarily by: ABO members; ABR, Inc.; Alaska Department of Fish and Game; Phillips Alaska, Inc.; Arctic Audubon Society; BLM (Cooperative Agreement #1422L320A7-2005). Additionally, the Alaska Department of Fish and Game provided significant in-kind support.

Literature Cited

Askins, R.A., J.F. Lynch, and R. Greenberg. 1990. Population declines in migratory birds in eastern North America. Curr. Ornithol. 7:1-57.

Pogson T.H., A-M. Barber, S.L. McDaniel, and S.K. Springer. 1996. Creamer’s Field Migration Station fall summary report. Unpublished report.

Rappole, J.H., and M.V. McDonald. 1992. Cause and effect in population declines of migratory birds. Auk 111:652-660.

Table 1. Mist netting effort at Creamers Field Migration Station: spring 1992-2001.
	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001
Net Hours	6,903	10,552	11,252	12,731	12,411	7,548	6,982	7,180	6,177	5,137
Days of Netting	42	43	41	45	44	42	40	40	37	34
Range of Dates	4/24-6/15	4/25-6/12	4/25-6/14	4/25-6/15	4/25-6/14	4/25-6/14	4/25-6/13	4/25-6/15	4/25-6/14	4/25-6/7
Range in no. nets/day	16-29	16-33	27-47	36-47	33-45	26	26	24-26	21-26	17-26
One net hour =one hour of operation of a standard 12m mist net

Table 2. Total number of individuals captured (newly banded birds, returns from previous years, and mortalities) at CFMS during spring migration: 1992-2001.
Species	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	Total
Green-winged Teal (Anas creca creca)	0	0	0	0	0	1	0	0	0	0	1
Northern Pintail (Anas acuta)	0	0	0	1	0	0	0	0	0	0	1
Sharp-shinned Hawk (Accipiter striatus velox)	3	3	4	1	2	2	1	2	2	1	21
Northern Goshawk (Accipiter gentilis atricapillus)	0	0	0	0	0	0	0	0	0	0	0
Lesser Yellowlegs (Tringa flavipes)	0	0	0	0	2	1	0	9	0	1	13
Solitary Sandpiper (Tringa solitaria cinnamomea)	5	3	4	2	6	4	0	7	7	8	46
Least Sandpiper (Calidris minutilla)	0	0	0	0	1	0	0	0	0	0	1
Northern Hawk Owl (Surnia ulula)	0	0	0	0	0	0	0	1	0	0	1
Yellow-bellied Sapsucker (Sphyrapicus varius)	0	0	0	0	0	0	0	1	0	0	1
Downy Woodpecker (Picoides pubescens nelsoni)	0	0	1	2	2	1	1	0	1	2	10
Hairy Woodpecker (Picoides villosus septentrionalis)	1	0	0	0	0	0	5	0	0	0	6
Three-toed Woodpecker (Picoides tridactylus fasciatus)	0	0	0	0	1	0	0	0	0	0	1
Northern Flicker (Colaptes auratus luteus)	1	1	0	3	2	3	0	1	0	0	11
Alder Flycatcher (Empidonax alnorum)	2	11	8	8	4	3	5	1	0	0	42
Hammond's Flycatcher (Empidonax hammondii)	12	15	20	29	12	17	11	8	11	12	147
Tree Swallow (Tachycineta bicolor)	0	0	0	1	0	0	1	2	0	6	10
Violet-green Swallow (Tachycineta thalassina thalassina)	0	0	0	1	1	0	0	0	0	51	53
Cliff Swallow (Petrochelidon pyrrhonota)	0	0	0	0	0	0	0	0	0	1	1
Gray Jay (Perisoreus canadensis canadensis)	1	0	0	0	0	2	0	1	1	0	5
Black-capped Chickadee (Poecile atricapillus turneri)	8	6	8	7	10	5	5	10	0	10	69
Boreal Chickadee (Poecile hudsonicus hudsonicus)	1	2	2	0	2	0	1	4	0	1	13
Arctic Warbler (Phylloscopus borealis kennicotti)	0	0	0	0	1	0	0	0	0	0	1
Ruby-crowned Kinglet (Regulus calendula calendula)	20	1	5	7	7	4	4	0	1	0	49
Gray-cheeked Thrush (Catharus minimus aliciae)	16	14	21	12	22	4	14	11	2	2	118
Swainson's Thrush (Catharus ustulatus ustulatus)	28	51	58	49	84	28	39	20	13	10	380
Hermit Thrush (Catharus guttatus euborius)	1	0	1	0	4	1	4	0	2	0	13
American Robin (Turdus migratorius migratorius)	31	37	39	54	46	47	79	54	34	28	449
Varied Thrush (Ixoreus naevius meruloides)	21	1	0	3	0	0	0	0	1	0	26
American Pipit (Anthus rubescens)	0	0	0	0	0	0	0	0	1	0	1
Bohemian Waxwing (Bombycilla garrulus pallidiceps)	0	0	0	0	0	0	1	0	0	1	2
Orange-crowned Warbler (Vermivora celata celata)	40	55	51	53	36	22	53	36	13	11	370
Yellow Warbler (Dendroica petechia banksi)	46	29	41	9	22	10	12	4	10	27	210
Table 2. Total number of individuals captured (newly banded birds, returns from previous years, and mortalities) at
CFMS during spring migration: 1992-2001.
Species	1992	1993	1994	1995	1996	1997	1998	1999	2000	2001	Total
Yellow-rumped Warbler (Dendroica coronata hooveri)	109	99	55	91	86	75	99	80	126	64	884
Blackpoll Warbler (Dendroica striata)	19	8	24	0	8	3	7	2	0	12	83
Northern Waterthrush (Seiurus noveboracensis)	23	14	67	25	54	25	14	15	9	9	255
Wilson's Warbler (Wilsonia pusilla)	33	54	58	61	17	13	14	9	8	2	269
American Tree Sparrow (Spizella arborea ochracea)	36	1	9	9	24	1	12	4	10	3	109
Savannah Sparrow (Passerculus sandwichensis anthinus)	57	17	37	33	59	17	38	22	18	12	310
Fox Sparrow (Passerella iliaca zaboria)	10	4	9	9	10	2	7	0	4	4	59
Lincoln's Sparrow (Melospiza lincolnii lincolnii)	6	5	12	23	14	7	22	12	1	2	104
Golden-crowned Sparrow (Zonotricia atricapilla)	0	1	0	0	0	0	0	0	0	0	1
White-crowned Sparrow (Zonotrichia leucophrys gambelii)	14	9	21	12	10	13	30	16	14	12	151
Dark-eyed Junco (Junco hyemalis hyemalis)	29	12	26	42	99	39	49	44	38	27	405
Lapland Longspur (Calcarius lapponicus alascensis)	0	0	1	0	0	0	0	0	0	0	1
Rusty Blackbird (Euphagus carolinus carolinus)	6	3	6	3	1	1	1	4	4	5	34
White-winged Crossbill (Loxia leucoptera leucoptera)	0	2	0	0	0	0	0	1	0	0	3
Common Redpoll (Carduelis flammea)	81	21	237	90	10	17	639	45	118	128	1,386
Hoary Redpoll (Carduelis hornemanni)	67	0	6	0	0	0	0	0	0	1	74
Pine Siskin (Carduelis spinus)	0	0	0	0	0	0	0	0	0	1	1
Total	727	479	831	640	659	368	1,168	426	449	454	6,201
Net Hours of Operation	6,865	10,552	11,252	12,731	12,411	7,548	6,982	7,180	6,177	5,137	86,835

Table 3. Capture rate (birds/1000 net hours) of birds during spring migration at Creamer's Field Migration Station: 1992-2001.
Species	92	93	94	95	96	97	98	99	00	01	Average
Alder Flycatcher	0.29	1.04	0.71	0.63	0.32	0.40	0.74	0.14	0.00	0.00	0.48
Hammond's Flycatcher	1.75	1.42	1.78	2.28	0.97	2.25	1.63	1.11	1.78	2.34	1.66
Gray Jay	0.15	0.00	0.00	0.00	0.00	0.26	0.00	0.14	0.16	0.00	0.06
Black-capped Chickadee	1.17	0.57	0.71	0.55	0.81	0.66	0.74	1.39	0.00	1.95	0.70
Boreal Chickadee	0.15	0.19	0.18	0.00	0.16	0.00	0.15	0.56	0.00	0.19	0.15
Ruby-crowned Kinglet	2.91	0.09	0.44	0.55	0.56	0.53	0.59	0.00	0.16	0.00	0.57
Gray-cheeked Thrush	2.33	1.33	1.87	0.94	1.77	0.53	2.07	1.53	0.32	0.39	1.36
Swainson's Thrush	4.08	4.83	5.15	3.85	6.77	3.71	5.77	2.79	2.10	1.95	4.39
Hermit Thrush	0.15	0.00	0.09	0.00	0.32	0.13	0.59	0.00	0.32	0.00	0.15
American Robin	4.52	3.51	3.47	4.24	3.71	6.23	11.69	7.52	5.50	5.45	5.09
Varied Thrush	3.06	0.09	0.00	0.24	0.00	0.00	0.00	0.00	0.16	0.00	0.30
Orange-crowned Warbler	5.83	5.21	4.53	4.16	2.90	2.91	7.84	5.01	2.10	2.14	4.27
Yellow Warbler	6.70	2.75	3.64	0.71	1.77	1.32	1.78	0.56	1.62	5.26	2.41
Yellow-rumped Warbler	15.88	9.38	4.89	7.15	6.93	9.94	14.64	11.14	20.40	12.46	10.11
Blackpoll Warbler	2.77	0.76	2.13	0.00	0.64	0.40	1.04	0.28	0.00	2.34	0.96
Northern Waterthrush	3.35	1.33	5.95	1.96	4.35	3.31	2.07	2.09	1.46	1.75	2.93
Wilson's Warbler	4.81	5.12	5.15	4.79	1.37	1.72	2.07	1.25	1.30	0.39	3.11
American Tree Sparrow	5.24	0.09	0.80	0.71	1.93	0.13	1.78	0.56	1.62	0.58	1.26
Savannah Sparrow	8.30	1.61	3.29	2.59	4.75	2.25	5.62	3.06	2.91	2.34	3.54
Fox Sparrow	1.46	0.38	0.80	0.71	0.81	0.26	1.04	0.00	0.65	0.78	0.68
Lincoln's Sparrow	0.87	0.47	1.07	1.81	1.13	0.93	3.25	1.67	0.16	0.39	1.20
White-crowned Sparrow	2.04	0.85	1.87	0.94	0.81	1.72	4.44	2.23	2.27	2.34	1.73
Dark-eyed Junco	4.22	1.14	2.31	3.30	7.98	5.17	7.25	6.13	6.15	5.26	4.64
Rusty Blackbird	0.87	0.28	0.53	0.24	0.08	0.13	0.15	0.56	0.65	0.97	0.39
Common Redpoll	11.80	1.99	21.06	7.07	0.81	2.25	94.53	6.27	19.10	24.92	15.99
Hoary Redpoll	9.76	0.00	0.53	0.00	0.00	0.00	0.00	0.00	0.00	0.19	0.85

Table 4. Participants in ABO education programs: 25 April-13 June 2001.
Program	Number of Programs	Number of Participants
Banding Demonstration	29	645
Invited Programs	4	62
Workshops, Walks, Seminars	5	448
Summer Adult Groups	3	42
Summer Youth Groups	1	12
Independent Visitors	na	43
Total	42	1,252